In an environment where a data storage device, such as a hard disk drive (HDD), a hybrid drive (comprising rotating magnetic media and non-volatile semiconductor memory), or a network attached storage (NAS) device, receives power from a host, negative voltages (such as negative voltages) on the host supply line may result in catastrophic failures depending on the amplitude of the negative voltage. For example, negative voltages have been an issue for certain HDDs and have been linked to heads-on-media failures.
In an effort to test for susceptibility to negative voltages, some HDD manufacturers have used poorly designed consumer power supplies to generate the negative voltages. However, the poorly designed consumer power supplies generally provide inconsistent negative voltages that are undesirable for a reliable negative voltage test process. Thus, it is desirable to provide a negative voltage testing methodology and tester for reliable negative voltage testing.